[Effects of tissue factor pathway inhibitor-1 on no-reflow in a rabbit model]

To investigate the role of plasma tissue factor (TF) and tissue factor pathway inhibitor-1 (TFPI-1) level and to observe the effect of extrinsic TFPI-1 on no-reflow (NR) in a rabbit model of ischemia/reperfusion.Rabbits were randomized into four groups (n = 10 each): ischemic- reperfusion group (IR, subjected to 120 minutes of coronary artery occlusion and followed by 60 minutes of reperfusion); ischemic- reperfusion TFPI-1 group (100 ng/kg bolus and 1 ng x kg(-1) x min(-1) infusion during reperfusion); ischemic group (subjected to 180 minutes of coronary artery occlusion) and sham group. The NR area and ischemic area were determined by thioflavin S and Evan's blue staining in vivo. Plasma TF and TFPI-1 levels were measured before operation, before and at 120 minutes post coronary artery ligation, 10 and 60 minutes after reperfusion by ELISA.Plasma TF and TFPI-1 levels before and at 120 minutes post coronary artery ligation were similar among the four groups (all P0.05). At 10 and 60 minutes after reperfusion, the plasma TF levels in the IR group was significantly higher than those in ischemic group and sham group [10 minutes: (20.7 + or - 4.1) pg/ml vs. (13.9 + or - 2.2) pg/ml (P0.001), (20.7 + or - 4.1) pg/ml vs. (13.2 + or - 2.6) pg/ml (P0.001); 60 minutes: (15.8 + or - 2.6) pg/ml vs. (13.5 + or - 1.6) pg/ml (P0.05), (15.8 + or - 2.6) pg/ml vs. (12.1 + or - 0.7) pg/ml (P0.001)] while the plasma TFPI-1 levels were similar among IR, ischemic and sham groups at 10 minutes after reperfusion and at 60 minutes after reperfusion (all P0.05). TFPI-1 level [(9.7 + or - 1.6) ng/ml] was significantly lower in the IR group than in the ischemic group [(11.6 + or - 1.6) ng/ml, P0.05] and sham group [(10.1 + or - 1.3) ng/ml, P0.01]. TF mRNA expression in the NR area in IR group was significantly up-regulated compared to the ischemic group (P0.05) and sham group (P0.001) while TFPI-1 mRNA expression was similar between IR group and ischemic group (P0.05). NR severity in the ischemic-reperfusion TFPI-1 group was significantly attenuated compared to IR group (0.39 + or - 0.11 vs. 0.54 + or - 0.06, P0.01).Upregulated TF mRNA expression in the NR area and increased plasma TF level during reperfusion period, reduced plasma TFPI-1 level during reperfusion period as well as attenuated NR severity by extrinsic application of human rTFPI-1 in this model suggested an important role in the pathogenesis of the NR phenomenon.